The benefits of air filters to remove dust, pollen and impurities from circulating air within a building are well recognized in the art. Air filters are commonly used in proximity to heaters and air conditioning units. The filtered air is typically routed through air ducts to various locations within a building, such as a home or office. It is well known that dust, pollen and other air impurities accumulate in the air delivery ducts. Thus, the filtered air is contaminated by the air impurities in the air delivery ducts, prior to being circulated in a room located in a building, such as a home or an office.
To overcome this difficulty, prior art air filters have been mounted in the air duct beneath the grill. To accomplish this, the air duct grill must be removed in order to replace the air filter. Since these air filters need to be periodically replaced or cleaned to operate efficiently, the air duct grill must be removed and reinstalled, each time the air filter is cleaned or replaced. With the filter positioned behind the grill register, it is difficult to visually determine when the filter needs changing. Prior art devices require the grill to be removed to inspect the filter, in order to determine when the filter needs changing. This is time consuming and labor intensive.
Other attempts to overcome these difficulties include grills that slide, pivot or hinge to receive the air filter. This increases the complexity of the air filter housing, increases costs, and requires a large inventory of air filters and air filter housings to fit the many sizes of air ducts found in homes and offices.
All prior art filters utilized to remove dust, pollen and impurities from circulating air within a building somewhat reduce the flow of air through the air ducts of the building. Other attempts to provide air duct filters have reduced the air flow in the ducts more than desired. Thus, a filter housing which does not reduce the air flow within the air ducts in the homes and offices in which the filter housings are utilized, or are provided with structure which actually improves the air flow through those ducts would be highly desirable.
Thus, many sizes of air filters and air filter housings must be manufactured, transported and sold, in order to accommodate the need for various sizes of air ducts. This requires additional storage and shelf space, as well as creating confusion as to which size of air filter and air filter housing are required for each air duct in a home or office.
Examples of prior art air filter housings known in the art include:
U.S. Pat. No. 5,947,815 issued to Danforth on Sep. 7, 1999. This invention discloses an air register filtering system having a frame, with an air filter enclosed within the frame. A top cover is hinged to the frame, and must be opened, to access the air filter.
U.S. Pat. No. 5,863,310 issued to Brown on Jan. 26, 1999, discloses a grill/filter mounting assembly where the grill is hinged to the duct, and must be sized to fit an existing duct.
U.S. Pat. No. 5,792,230 issued to Moore et al on Aug. 11, 1998, discloses an air register having a filter element. A pivotable retaining plate engages the face plate to retain the filter across the openings of the register.
U.S. Pat. No. 4,344,899 issued to McConnell on Jun. 15, 1982, discloses a snap on air duct filter assembly having first and second frames.
U.S. Pat. No. 2,575,499 issued to Manow on Nov. 20, 1951, discloses a slide-in fiberglass filter received in a hinged housing sized to fit an air duct.
U.S. Pat. No. 1,914,397 issued to Bender on Jun. 20, 1933, discloses a dust shield for warm air registers. This patent teaches a dust shield held in a securing means above a register.
U.S. Pat. No. 1,801,794 issued to Broudy et al on Apr. 21, 1931, discloses a register filter secured to a hot air register.
U.S. Pat. No. 1,726,792 issued to Altman et al on Sep. 3, 1929, discloses an adjustable register screen pivoted to a frame.
U.S. Pat. No. 1,694,089 issued to Wright on Dec. 4, 1928, discloses a register duct cover which is removed to gain access to a filter.
U.S. Pat. No. 1,429,811 issued to Tynan on Sep. 19, 1922, discloses a register attachment which includes a casing, a pane, and screens which are sized to fit an air duct.